Tour of the NW End of Sylvan Lake to Check the State of Spring Runoff.

The eagle is back in its nest high in a tree on the south edge of the Sylvan Lake Natural Area.

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Here is a photo album of a driving tour of the Northwest Creek catchment including manure-rich feedlots, evidence of spring runoff, but no flow in the creek itself on May 13.

The whole area was very dry although there was flow channel erosion and flattened grass from recent runoff at some locations. Up in the feedlot area at the top of the hill where Northwest Creek starts, the topography suggested that runoff tends to be trapped in many depressions and ponds that evaporate, so nutrients leached from the manure piles that you can see in the photos are not guaranteed to reach the lake.

The net result of this photo survey is that the stormwater runoff threat from that area is currently low. The final two photos are of Northwest Creek on the north and south sides of Rainy Creek Road. There was no flow through the main, small-diameter culvert. Precipitation of more than a few cm of monsoon-type rain will be needed to saturate the ground and restart any surface flow into the lake.

Just a small fraction of the typical annual precipitation of 0.5 m is actually in play as surface flow as these maps show of the the evaporation/transpiration rates for this area.

The eagle did not seem to be concerned about the state of Northwest Creek.

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